Add back call blacklist backend.

Change-Id: I065f1c206cbb86b790e698b396cc611c9a434279
Add back in-call vibration.

Change-Id: Id229f73a13e58168f0cceee1c4d4c5477384e889
Fix 'vibrate outgoing' behaviour.

Change-Id: I08d05dcf03074af73e9fcf9a2f9788cd46b27833
Cleanup: get rid of getCurrentCall() method.

The only caller was the vibration code, which only used it when the call
is picked up. As a picked up call is always the foreground one, we can
safely just use that.

Change-Id: Id3e4f9d3738bfe72387899802b89202bfef61646